The invention relates to an apparatus for controlling an automatically shifting transmission having at least one selector device by way of which at least the driving stages P, R, N, D, which can be set in an automatic mode, can be defined.
An apparatus of this kind is known, for example, from DE 10 2007 023 267 A1. This known apparatus has a first selector device in the form of a selector lever in an automatic gate, with which selector lever at least the driving stages P, R, N, D which can be set in an automatic mode can be defined. An automatic gear selection can be carried out, in particular, in the driving stage D. A second selector device is used to manually shift up or shift down the gears of the transmission in steps in a manual mode. The second selector device can be provided, for example, in the form of two switches, which are integrated in the steering wheel or in the form of two switches which are integrated in a manual gate of the selector lever. The known apparatus has at least one electronic transmission control device, which is customary in automatic transmissions or automated manual transmissions.
Furthermore, it is known to change the motor vehicle into a so-called transportation mode after the production process of the motor vehicle, for example by way of a diagnostic tester or automatically when certain operating conditions are present (DE 10 2008 061 957 A1). In this case, according to the prior art, corresponding pre-specification of a maximum permissible engine rotational speed in an electronic engine control unit for example prevents the engine of the motor vehicle from being overrevved when loading the motor vehicle or when maneuvering the motor vehicle before or after transportation. Such overrevving disadvantageously subjects component to loading.
The object of the invention is to also provide protection for automatic transmissions or automated transmissions in the transportation mode.
According to the invention, this and other objects are achieved by a motor vehicle comprising an apparatus for controlling an automatically shifting transmission having at least one selector device by way of which at least the driving stages P, R, N, D, which can be set in an automatic mode, can be defined. The motor vehicle further comprises an electronic transmission control unit by way of which shift elements of the transmission for selecting a respectively prespecified gear can be actuated depending on signals from the selector device and further input signals. The control unit also receives, as an input signal, the state of a transportation mode. A transportation mode functional module is provided by which only the forward gears can be selected in the active transportation mode. The weakest shift element (in this case the clutch) of the transmission always is closed in the forward gears.
Using the apparatus according to the invention, in particular by appropriate programming of the/an electronic transmission control unit in the active transportation mode of a motor vehicle, only the forward gears can be selected, the weakest shift element, in particular the weakest brake or clutch in an automatic transmission, always being closed in the forward gears.
Preferably, manual shifting options in an electronically controlled automatic transmission with a manual mode are additionally suppressed.
The invention advantageously minimizes or eliminates the repeated occurrence of destroyed clutches in automatic transmissions due to excessively high shift loadings in motor vehicle loading processes during transportation.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.